The present invention is related to radio controlled, railway train brake systems and particularly to such systems in which the train locomotive and caboose are equipped to concurrently establish a reduction of the train brake pipe pressure from opposite ends at the time of a brake application.
Heretofore, remote brake control systems for railway trains have relied upon radio transmission of a brake control signal for a time duration predicated upon the degree of brake application desired. Fluid pressure in an equalizing reservoir at the caboose corresponding in size to the locomotive equalizing reservoir is vented via an orifice having a flow capacity corresponding to the flow capacity of an orifice via which the locomotive equalizing reservoir pressure is vented. Since the duration the equalizing reservoir pressure reduction occurs at the locomotive corresponds to the duration of the transmitted brake control signal, the caboose equalizing reservoir pressure reduction is intended to correspond to the reduction at the locomotive, with the resultant degree of brake pipe reduction and thus the brake application effective at each car of the train being substantially equal. In that these flow orifices are thus critical in obtaining equal braking along the train, it will be appreciated that accumulation of dirt or other foreign matter around these orifices can have an adverse effect on the operation of the brake control system. Furthermore, a brake control signal transmitted on a timed basis according to the desired brake application has the disadvantage of being inaccurate as a result of any temporary loss of radio communication, which is not uncommon.